Seismic response of large diameter shield tunnel in complex subsea formations

Based on the Zhuhai Shizimen Tunnel Project, this study discussed the seismic response of large diameter shield tunnel in complex subsea formations. A two-dimensional finite element model of shield tunnel was established, the stress distribution and displacement of shield tunnel in the consolidation stage after earthquake were analyzed. The results showed that under the action of 0.3g amplitude earthquake, the tunnel with a buried depth of 40 meters has the highest degree of liquefaction. The vertical displacement of the tunnel is 9.5 times lower than that of the buried depth of 35 meters, and the downward float in the consolidation stage is reduced by 71%. The maximum value of shear force, axial force and bending moment with a buried depth of 40m are at the arch waist. While the maximum value of shear force, axial force and bending moment of the tunnel buried 35m occurred at the bottom of the arch, the bottom of the arch and the vault, the bottom of the arch and the lower 45 degrees of the arch waist, respectively.